C1 expanding polynomials with 4 brackets help

Recently started studying a-levels at sixth form. I am comfortable expanding polynomials when there are two brackets or when being cubed but cannot seem to work out how to expand one with four brackets:

(x+1)(x+4)(x-2)(x-3)

when working out I am getting a different answer to the one given in the book. Please don't just tell me the answer because I am already aware of that it is x^4-15x^2+10x+24 but unsure how to get to this answer. Help with the method would be greatly appreciated

Thanks in advance!

Multiply the first 2 brackets
Multiply the second 2 brackets

You now have 2 quadratics
Multiply those

This is the method I tried and got the answer: X^4 -2x^3-5x^2-2x+24

Where am i going wrong?

No idea

Can you show your working

What were your 2 quadratics
What were the 9 expansion terms

I get what the book gets

my two quadratics are x^2 + 3x +4 and x^2-5x +6

No idea

Can you show your working

What were your 2 quadratics
What were the 9 expansion terms

I get what the book gets

There is your error

Oh, I made an error when multiplying the two brackets so is it:

X^2 + 5x +4?

yes